Record transmission system



Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMISSION SYSTEM 18 Sheets-Sheet l Filed Deo. 14, 1959 ATTORNEYS Nov. 16, 1965 R. A. BARBEAU 3,218,508

RECORD TRANSMISSION SYSTEM Filed DSC. 14, 1959 18 Sheets-Sheet 2 o Mm M @o --ll C O l m" M, @QQ @Q a .ML CDO "5m um o Q a w @OO @O H- o s OOO@ .com O G "gag m@ o @C O00@ "P- L.: OO@ Q -m QGOQQ@ P- Jm 0 2 -lm MNE',

w o@ @0 M w OO GO M O N-lrO 'l- O mlm- MLBQLQQM w @GO @C @C C YM@ ILL @O O O M, @Oo OQ m -m @C 5" on: O Q Q Lw OQO um (mi @000 Qor O C Q Ng m@ o @Q @ggf @GOG "Q 9g @00 @Qi GGOQO@ M @000Go @Q n 0006@ m9 D @o @o m D OO O0 "m @(30 NN fL- GOO N" w oo@ o@ 2g WM J l I3 I9 23 225 30 32 TOTAL (PUNCHING) TOTAL (READING) R. A. BARBEAU 3,218,608

RECORD TRANSMISSION SYSTEM 1959 18 Sheets-Sheet 5 No2 2oz m500 Vmru mmm m D mm201 ZIO*J Q2 oz/ V604 @gom E! Emmh@ I lullj mm S30 Nov. 16, 1965 Filed Dec. 14,

Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMISSION SY Filed Dec. 14, 1959 STEM 18 Sheets-Sheet 4 Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMISSION SYSTEM 18 Sheets-Sheet 5 Filed Deo. 14, 1959 I Mp3-914 Nov. 16, 1965 Filed Dec. 14, 1959 R. A. BARBEAU RECORD TRANSMISSION SYSTEM 18 Sheets-Sheet 6 Nov. 16, 1965 R. A. BARBEAU 3,218,608

RECORD TRANSMISSION SYSTEM Filed Deo. 14, 1959 18 Sheets-Sheet '7 To CQUNTER @mmm FIG. 5b

WITH RELAYS NUMBERED II TO 2O COUNTER 62-2 FIG. 5c

HOLD CIRCUIT 8 CARRY RELAYS` FOR COUNTERS 62-2 l COM PARE CIRCUIT FIG.5d

Nov. 16, 1965 R. A. BARBEAU 3,218,608

RECORD TRANSMISSION SYSTEM Filed Deo. 14, 1959 18 Sheets-Sheet 8 TO INT MAGS COUNTER READOUT l ENCODE NETWORK |46 CAM 31 80-5 PUNCH CLUTH Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMISSION SYSTEM Filed Deo. 14, 1959 18 Sheets-Sheet 9 Nov. 16, 1965 R. A. BARBEAU RECORD TRANsMlssIoN SYSTEM 18 Sheets-Sheet 10 Filed Dec. 14, 1959 FIG.5g

Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMI SSION SYSTEM Nov. 16, 1965y R. A. BARBEAU RECORD TRANSMISSION SYSTEM 18 Sheets-Sheet 12 Filed Dec, 14, 1959 ADD PUL TO FIG. 6

Nov. 16, 1965 R. A. BARBEAU RECORD TRANSMISSION SYSTEM Filed Dec. 14, 1959 18 Sheets-Sheet 13 a TAPE i, ls M -E3 I so TAPE READER 252 UN|T TAPE GODE ANALYzlNG DMT -f254 DATA STORAGE 2; 256) 280 f PAGE GARD MAG CORE TAPE CONTROL f PR|NTER PUNCH DRUM STORAGE UNiT T l ERROR MEMORYl G E (29e v o Z E OHEOK 1ND|OATE 56 O ERROR INDTOATE `38 BIT O DE ADDER CSECK COMPARE Nov. 16, 1965 R. A. BARBEAU 3,218,608

RECORD TRANSMISS XON SYSTEM FIG.8O

Nov. 16, 1965 R. A. BARBEAU 3,218,608

RECORD TRANSMISSION SYSTEM Filed Dec. 14, 1959 18 Sheets-Sheet 15 j CAM 23e COUNTER sETUP LJ i RELAY POINTS I 2 l 3 1 COUNTER 268.4 4 RELAYS i 292 201 TO 21o I L 5 i l 6 1 l T li --l L j I jl 278/ COUNTER SETUP 252 1 4| @1 5 RELAYS f LJ 211-1 CHANNEL1 f302 TAPE CHANNEL2 I 2m READER C A NE Y H N l" CHANNEL3 1 SWXX 2113 CHANNEL4 321m 211-5 CHANNEL 5 272-15 CHECK TEST V 22 lR -1 CAM 235 j r-T- 1 1 MACH1NE 1 1 1 I P-T l f L L 1 L .L 1 B20-2 STOP 1 CIRCUITS 1 STORAGE ENTRY RELAY 5 -J 26E*ENADO 1 2681`AOD 2 29e L 2942/! T T-'1 1"T-1 |r\1 l 1 1 1 1 1 1 I 1 1 H p L J 1 L L 1 L L 1 296 272-2C0MP/2 ERROR M MORY 260 T11-TI LA; 27o-5 COMPAR1NO CAM 237 27013 RELAYS T H R r --1 304-2 26e-9 270 l l [VTT-1 {TTT-7 |ANALYzED 1 1 l1 1 1 2v2-3 l L 1 J LF CODE 1% Ti-J L 1 OUTPUT \L 1 /CAM 24o H P 272 :CAM 234 TIMEIQSG3 L 1 J I @ECAM 239 -CAM 241 f STORAGE ENTRY Fl G. 8 b 30o 255%l 294- RELAY DATA l H p 294 STORAGE Nov. 16, 1965 R. A. BARBEAU 3,218,608

RECORD TRANSMISSION SYSTEM L) )XL R. A. BARBEAU RECORD TRANSMISSION SYSTEM Nov. 16, 1965 18 Sheets-Sheet 1'7 Filed Dec. 14, 1959 om m moco a mjoro @Q4 ZOZ OEmE mu ZOFOMCME QQQ ZOZ F3n-PDO mu OmOOO Il .DnTrDO @O m @m500 Iilllli Ilmd 135m Sou 95mm HES/ 2mm l1 SN 5:5

mmm mmm 24U mmm www Edd R. A. BARBEAU RECORD TRANSMISSION SYSTEM Nov. 16, 1965 18 Sheets-Sheet 418 Filed Deo. 14, 1959 xom Io xOmIO Fmmm lIIrIIx alllll N a o md5 mo/Em m15 o mf# Do United States Patent O M 3,218,608 RECORD TRANSMISSION SYSTEM Raymond A. Barbeau, Poughkeepsie, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Dec. 14, 1959, Ser. No. 859,441 8 Claims. (Cl. S40-146.1)

This invention relates to improvements in record transmission systems and more particularly to a telegraphic tape handling system wherein the accuracy of the data recording on a tape can be checked for accuracy.

Communication systems Which transmit data to different points and utilize a tape both in transmission and in conversion are quite useful in the data processing arts, for example, in central account machines for the preparation of payrolls, billing or the like. The accuracy of data transmitted is essential to the effective operation of such a system. In the past much effort has been directed to checking and improving the accuracy of data transmission systems, including transmission systems in which data is transferred from a record for transmission and reconverted to place the information back on a record after transmission.

AOne type of prior checking system for a telegraphic tape handling apparatus is disclosed in the application of Barbeau et al. Serial No. 553,601, filed December 14, 1955, now Patent No. 2,958,727, for Checking Systems for Record Data Transmission. This prior art system accurately checks the tape as it is prepared for transmission and after transmission for conversion, e.g., the tape checkable tape system checks the accuracy of tape preparation column by column and message by message. The units order of the total number of like data bits in any one message is entered into the tape as a check code at the end of the message and this is compared or checked after preparation and after transmission to determine whether or not the units order of the number of like data bits in the message prepared is the same as the units order of the number of like data bits transmitted or received.

Although such a system as described in the aforementioned application will catch most of the errors in data transmission there is still a possibility where such a system might fail to catch some possible errors. Because the accuracy of any data transmission system is absolutely essential to its reliable operation it is the primary object of this invention to provide a checkable telegraphic tape handling system which will indicate an error if there is misfeeding of the tape, mutilation of signals or dropping or adding of ten or a multiple of ten like data bits of information while adding lor dropping tape columns.

During the initial preparation of record data tape such as paper tape in a serial sequence by cycles, if misfeeding of the tape should occur it is possible to record two cycles of information in one tape column. Due to the code structure, for example, with paper tape using a vebit code, it is possible to punch the second and third -channels to indicate 'one letter in one column and to punch the first, fourth and fifth channels which should be in the next column in the same column as the two and three positions were punched, thus giving a total of five like data bits in one column wherein there should be five like data bits in two adjacent columns. The counting mechanism, if it merely counts the number like data bits punched, would count only the number of like data bits, e.g., five, to be included in the check code and the error would not be detected. During record conversion the misfeed would not be detected and the error in the message would not be detected.

An error of the nature described above could not only 3,218,608 Patented Nov. 16, 1965 lCC occur in the tape preparation for transmission but also in the transmission from 4one station to another and in the tape repreparation at a receiving station. The insertion of a check digit at the end of the message will not provide the necessary error checking function if there is a column mis-feed and the total like data bits remain the same, such as in the prior art system described above.

Other possible errors are known as compensating errors within a message. In other words, one message may be scrambled during transmission over communication lines such that a plurality of like data bits may be dropped and an equal number of like data bits may be added, thus the total number of like data bits in one message will be the same as the number of like data bits which should have been transmitted. However, if a column is dropped during the transmission or at any other time, the mechanisrn of this invention will detect that the message is in error even if there is a compensating error in the number of like data bits transmitted.

It is also conceivable that during transmission or tape preparation or re-perforation a number of tape columns could be dropped or lost. 1f this number of tape columns contained like data bits which are a multiple of 10, the check digit of the number of like data bits in the tape would be the same as the check digit of the number of like data bits which should have been transmitted; therefore, with the prior art apparatus no error can be detected. However, by counting the number of machine cycles, i.e., the number of cycles the punch or tape reader goes through and adding them to the number of like data bits in all the columns of a message, an error of this type will be detected.

Another possibility for introducing an error in a telegraphic tape transmitting system is in the case of a transmitter failing to escape and possible punching all five channel positions an even number of times. If this happens, the total number of like data bits would be a multiple of l0 which would produce a check digit having the same units order as the correct number of digits which should have been transmitted. However, if the number of columns or punching cycles are added, and this is used as the digit, an error of this type will not go undetected.

It is an object of this invention to provide the necessary apparatus and controls for detecting errors such as those described above caused by such malfunction of the machinery and for preventing the processing of information if such errors exist. The detection of such errors can be readily accomplished by a relatively simple apparatus disclosed in this application.

It is another object of this invention to provide a check on the number of tape columns contained in a record message. This control is put in at the time of tape preparation and checks the complete system from tape reading to conversion. Regardless of the means of tape preparation, tape transmission and re-preparation, as well as tape reading for conversion, column check for record control is in effect.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings which disclose, by way of example, the principle of this invention and the best mode which has been contemplated, of applying that principle.

In the drawings:

FIG. l is schematic showing of the improved tape processing and error checking system of this invention;

FIG. 2a is an illustration of a punched paper tape for transmitting the message IBM and shows how the prior art apparatus checks the total number of like data bits in a message and introduces the units order of this total as a check code at the end of the message;

FIG. 2b illustrates one type of error which can be caused by mis-feeding of the paper tape in either tape preparation or in reproduction or in transmission, wherein a column is dropped, and shows how the prior art apparatus, by counting the total number of like data bits in a message, will fail to detect this error;

FIG. 3a illustrates a paper tape prepared for transmitting the message IBM and shows the count for the number of like data bits plus the number of column cycles the machine attempts to go through and the entering of a check digit in the check position in accordance with the teachings of this invention;

FIG. 3b shows how the apparatus of this invention will catch an error of the type shown in 2b caused by misfeeding of a tape column;

FIG. 4 is a sequence chart or timing diagram;

FIG. 5a through 5i is a wiring diagram of the tape preparation equipment;

FIG. 6 is a timing chart;

FIG. 7 is a diagrammatical representation of the tape conversion equipment employed in the tape processing system of this invention;

FIG. 8a through 8c is the wiring diagram of the conversion equipment;

FIG. 9a and 9b is a timing of sequence chart of the operation of the conversion equipment.

Briefiy, this invention is an improvement on that described in copending application Serial No. 553,001, the improvement providing a checkable tape record length control whereby a discrepancy in the number of like data bits and the number of columns in a message can be detected to prevent the processing of data in a message which is an error. Such errors might occur during misfeeding during tape preparation, transmission, or reperforation, and/ or occur by column and like data bit addition or dropping during transmission over leased wires or other media. More specifically, the apparatus of this invention contemplates adding to the number of like data bits in each column or cycle of the machine a numeric 1 and obtaining a total to be entered as a check digit which total will represent the number of like data bits and the number of column cycles of the machine. Therefore, if there is any discrepancy between the total number of like data bits and number of columns in the record and the number of data bits and columns which should be in the record the error will be detected.

The essence of this invention and its relationship to the prior art in function can be explained with reference to FIGS. 2a, 2b, 3a, and 3b. FIG. 2a shows a paper tape wherein the message IBM is to be transmitted, processed after transmission and IGIBMSM has been punched. It can be seen that the total number of like data bits, after the first (figures shift) has been entered, is counted and for this particular message the total number of like data bits is 24. Therefore, by an apparatus similar to that described in the aforementioned application the check digit 4 is entered into the check position after the Referring to FIG. 2b, there is shown a paper tape wherein the same message was attempted to be entered into the tape either during preparation for transmission or during reperforation (however, the same error could occur during transmission) and one column has been dropped. In other Words, the fifth and sixth columns have been superposed and the I code punching in channels 2 and 3 has superimposed upon it the code for B repreenting by punching and in channels 1, 4, and S. The

combined punching of all five channels in one column position is the code for letter shift In counting the like data bits of each column cycle of the message the total number of such bits is the same as the correct tape of FIG. 2a, namely 24, and the units order digit, 4, is entered as a check code onto the record. Thus, the check code 4 of the tape will be the same as the cheek code for the tape which should have been prepared and the error, caused by mis-feeding or the like, will not be detected.

FIG. 3a shows the same message as punched in the tape of 2a. However, the number of cycles the machine goes through in punching is added to the total number of like data bits as shown in FIG. 3a with the resulting total of 33, therefore the units order digit, 3, is entered in the check code column position.

FIG. 3b shows what will happen if there is an error similar to that shown in FIG. 2b, .e., a mis-feeding or other error causing superposition of columns 5 and 6 and punching all channel positions producing the same number of total like data bits and a different number of columns. During original tape preparation, by adding the punching cycles to the total number of like data bits the resulting total is 33 and the check digit 3 is entered into the check position. Since the check digit 3 of the tape read for further processing will not compare with the check digit 2 generated during the tape reading for processing, the error will be detected by comparison means and the incorrect message or data will not be processed. In other words, during tape reading, by adding numeric l for each reading cycle or tape column, the column mis-feed is readily detected as shown by comparison of the reading and punching like data bit plus cycle totals in FIG. 3b.

FIGS. 2b and 3b illustrate only one type of error, and that is where two column punchings are placed in the same column to give an incorrect message. However, numerous other types of errors can occur in data transmission systems resulting in a number of like data bits which is equal to a multiple of 10 above or below the correct number of like data bits which should be in the message. Unless the number of columns or machine cycles are added to the number of like data bits, errors such as these may go undetected. Such errors could occur where a number of complete columns containing like data bits which are equal to 10 or a multiple of l0 are either added or dropped in transmission of the message over leased wires or other communication media. Other errors caused by the addition and dropping of the same number of like data bits coupled with an incorrect transmission of the number of columns would also be detected by the detecting technique described above.

The apparatus of the detecting system is shown schematically in FIG. 1. This apparatus is generally similar to that shown in the aforesaid copending application with the exception that it has been modified to add numeric l to the electrical bit count unit #1, 62-1, and the mechanical bit count unit #2, 62-2 every time tape punch 56 goes through or attempts to go through a punching cycle. On the tape conversion end of the system after transmission the tape reader unit 252 has been modified to add numeric l to the bit adder 278 every time the tapereader unit goes through a reading cycle. The addition of numerical one is under control of the tape punch 56 rather than tape perforator control 52 in the tape preparation and in the tape conversion is under the control of tape reader mechanism 252, and is controlled by the timing cams therein as will be explained in detail hereinafter.

With reference to the remaining drawings, and in order to explain the operation of this apparatus invention, a length of telegraphic tape 50 is shown in FIG. 4 as hav- 

4. A MECHANISM FOR CHECKING FOR ERRORS IN MESSAGES IN A PAPER TAPE DATA TRANSMISSION SYSTEM COMPRISING: MEANS CONTROLLING A TAPE PUNCH IN TAPE COLUMN BIT CODE PUNCH CYCLES, CODE MEANS INDICATING THE BEGINNING AND END OF A MESSAGE IN SAID TAPE, MEANS COUNTING THE NUMBER OF LIKE CODE BITS AND THE NUMBER OF PUNCH CYCLES IN A MESSAGE, MEANS FOR ENTERING INTO SAID TAPE IN A COLUMN FOLLOWING AN END OF MESSAGE CODE A CHECK DIGIT CODE CORRESPONDING TO THE UNITS ORDER OF THE NUMBER OF LIKE BITS AND PUNCH CYCLES IN SAID MESSAGE, MEANS FOR READING SAID TAPE IN COLUMN CYCLES, MEANS RESPONSIVE TO THE OPERATION OF SAID TAPE READER FOR COUNTING THE COLUMN LIKE CODE BITS AND THE COLUMNS IN SAID MESSAGE, AND COMPARING MEANS FOR DETERMINING IN EACH MESSAGE, SAID CONMENT OR NON-AGREEMENT BETWEEN THE UNITS ORDER OF SAID READER CONTROLLED COUNTER AND SAID CHECK DIGIT CODE AT THE END OF SAID MESSAGE. 